The present invention relates to a method for accessing sets of data contained in mass memory, and to a device allowing the method-to be implemented. The device may be used particularly in magnetic tape players/recorders.
Mass memories are widely used to store relatively large quantities of data. A mass memory requires an information medium which may be formed, for example, by an optically or magnetically readable disk, a magnetic tape or even an electronic circuit on semiconductors. Depending on the mode of reading of the mass memory, and depending on the mode of arranging the data in the mass memory, access for reading the data may require more or less access time. The access time is caused, in large part, by the time which a read device takes to get into position to read the data to be read. The access times may reduce the efficacy of a mass memory when numerous data items arranged in this memory are to be accessed in a non-ordered way. This is the case, for example, of mass memory on a magnetic tape medium. The mass memory may contain data grouped together into sets of data, each set of data representing a song, for example. In order to gain access from one song to another song on the same magnetic tape, the songs being separated by a defined length of this magnetic tape, it is first of all necessary to make the entire defined length of magnetic tape move past the read device.
The problem to which the present invention proposes to afford a solution is that of eliminating certain drawbacks due to the access times during access to data in mass memory.
One solution to the problem posed, and according to the present invention, is found in a method for accessing a determined set of data among sets of data contained in a mass memory on an information carrier which comprises the steps of:
obtaining a command for access to the determined set of data,
after obtaining the command for access, reading introduction data from an introduction memory distinct from the mass memory but on the information carrier,
processing the introduction data read from the introduction memory,
realizing an access operation to the determined set of data at the same time as the step of processing the introduction data.
The processing of the introduction data may, for example, be the reproduction into music and/or into images when the introduction data are audio or video data.
According to one preferred embodiment of the access method according to the invention, processing is carried out on introduction data which are specific to the set of data which is the subject of the access operation.
The introduction data may, for example, constitute a subset of the set of data to be accessed.
The solution to the problem posed may according to the invention also be seen in a device for accessing sets of data contained in mass memory on an information carrier, access to a determined set of data for reading taking place during an access time. The device comprises an introduction memory containing introduction data, the introduction memory being separate from the mass memory but on the same information carrier. The device further comprises reading means for reading from the introduction memory, command means for obtaining a command for access to the determined set of data and being at least connected to the introduction memory, and processing means for processing the read introduction data, the processing means acting particularly during the time for accessing the determined set of data.
According to one preferred embodiment of the device according to the invention, the device comprises a temporary memory separate from the mass memory, transferring means for transferring at least a part of a set of data from the mass memory into the temporary memory while this set of data is read, further reading means for reading from the temporary memory and reproduction means for reproducing a set of data at a moment later than the reading of this set, these reproduction means being at least linked to the further reading means for reading from the temporary memory.
When the reading of a set of data is coming to an end, it is possible to continue to reproduce the data in deferred mode while, for example, further access is gained to another set of data.
Further characteristics and advantages of the present invention will emerge on reading the description given below of examples in accordance with the present invention, this description being given with reference to the attached drawings in which: